view hgext/automv.py @ 51347:555826073625

delta-find: introduce and use specialized _DeltaSearch class

For now, we introduce some very simple variant, but they are still useful to
display how having the class can helps keeping the simple case simple and
their special case out of more advanced logic.

# automv.py
#
# Copyright 2013-2016 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""check for unrecorded moves at commit time (EXPERIMENTAL)

This extension checks at commit/amend time if any of the committed files
comes from an unrecorded mv.

The threshold at which a file is considered a move can be set with the
``automv.similarity`` config option. This option takes a percentage between 0
(disabled) and 100 (files must be identical), the default is 95.

"""

# Using 95 as a default similarity is based on an analysis of the mercurial
# repositories of the cpython, mozilla-central & mercurial repositories, as
# well as 2 very large facebook repositories. At 95 50% of all potential
# missed moves would be caught, as well as correspond with 87% of all
# explicitly marked moves.  Together, 80% of moved files are 95% similar or
# more.
#
# See http://markmail.org/thread/5pxnljesvufvom57 for context.


from mercurial.i18n import _
from mercurial import (
    commands,
    copies,
    error,
    extensions,
    pycompat,
    registrar,
    scmutil,
    similar,
)

configtable = {}
configitem = registrar.configitem(configtable)

configitem(
    b'automv',
    b'similarity',
    default=95,
)


def extsetup(ui):
    entry = extensions.wrapcommand(commands.table, b'commit', mvcheck)
    entry[1].append(
        (b'', b'no-automv', None, _(b'disable automatic file move detection'))
    )


def mvcheck(orig, ui, repo, *pats, **opts):
    """Hook to check for moves at commit time"""
    renames = None
    disabled = opts.pop('no_automv', False)
    with repo.wlock():
        if not disabled:
            threshold = ui.configint(b'automv', b'similarity')
            if not 0 <= threshold <= 100:
                raise error.Abort(
                    _(b'automv.similarity must be between 0 and 100')
                )
            if threshold > 0:
                match = scmutil.match(
                    repo[None], pats, pycompat.byteskwargs(opts)
                )
                added, removed = _interestingfiles(repo, match)
                uipathfn = scmutil.getuipathfn(repo, legacyrelativevalue=True)
                renames = _findrenames(
                    repo, uipathfn, added, removed, threshold / 100.0
                )

        if renames is not None:
            with repo.dirstate.changing_files(repo):
                # XXX this should be wider and integrated with the commit
                # transaction. At the same time as we do the `addremove` logic
                # for commit.  However we can't really do better with the
                # current extension structure, and this is not worse than what
                # happened before.
                scmutil._markchanges(repo, (), (), renames)
        return orig(ui, repo, *pats, **opts)


def _interestingfiles(repo, matcher):
    """Find what files were added or removed in this commit.

    Returns a tuple of two lists: (added, removed). Only files not *already*
    marked as moved are included in the added list.

    """
    stat = repo.status(match=matcher)
    added = stat.added
    removed = stat.removed

    copy = copies.pathcopies(repo[b'.'], repo[None], matcher)
    # remove the copy files for which we already have copy info
    added = [f for f in added if f not in copy]

    return added, removed


def _findrenames(repo, uipathfn, added, removed, similarity):
    """Find what files in added are really moved files.

    Any file named in removed that is at least similarity% similar to a file
    in added is seen as a rename.

    """
    renames = {}
    if similarity > 0:
        for src, dst, score in similar.findrenames(
            repo, added, removed, similarity
        ):
            if repo.ui.verbose:
                repo.ui.status(
                    _(b'detected move of %s as %s (%d%% similar)\n')
                    % (uipathfn(src), uipathfn(dst), score * 100)
                )
            renames[dst] = src
    if renames:
        repo.ui.status(_(b'detected move of %d files\n') % len(renames))
    return renames